Add additional custom tab in WooCommerce myaccount page

custom-tab.php

<?php
/**
 *
 * Class for adding new custom tab in WooCommerce myaccount page.
 *
 * @class WooCommerce_Myaccount_Tab
 */
Class WooCommerce_Myaccount_Tab {

	/**
	 * Constructor.
	 */
	public function __construct() {

		// Return if WooCommerce is not installed.
		if( ! defined( 'WC_VERSION' ) ) {
			return;
		}

		add_action( 'init', array( $this, 'register_endpoint' ) );
		add_filter( 'query_vars', array( $this, 'query_vars' ) );
		add_filter( 'woocommerce_account_menu_items', array( $this, 'add_new_account_tab' ) );
		add_action( 'woocommerce_account_new-endpoint_endpoint', array( $this, 'add_content' ) );
	}

	/**
	 * Register New Endpoint.
	 *
	 * @return Void.
	 */
	public function register_endpoint() {
		add_rewrite_endpoint( 'new-endpoint', EP_ROOT | EP_PAGES );
	}

	/**
	 * Add new query var.
	 *
	 * @param array $vars vars,
	 *
	 * @return array.
	 */
	public function query_vars( $vars ) {

        	$vars[] = 'new-endpoint';
        	return $vars;
	}

	/**
	 * Add New tab in my account page.
	 *
	 * @param array $items myaccount Items.
	 *
	 * @return array Items including New tab.
	 */
	public function add_new_account_tab( $items ) {

		$items['new-endpoint']	= 'New Item';
		return $items;
	}

	/**
	 * Add content to the new tab.
	 *
	 * @return  void.
	 */
	public function add_content() {
		echo 'Contents here!';
	}
}

new WooCommerce_Myaccount_Tab();